Sol–Gel Synthesis and Simultaneous Oxidation ofLn2Ba2Cu2Ti2O11−δ☆

Abstract The synthesis of several substituted and unsubstituted derivatives of the series of layered perovskites Ln 2 Ba 2 Cu 2 Ti 2 O 11 by a sol–gel method is reported. Reduced synthesis temperatures were attained for La, Nd (750°C), and Eu (900°C) derivatives, whereas Tb derivatives could not be obtained by this method. The products were characterized by small particle sizes of 30–100 nm (compared to ∼800 nm for samples prepared by the classical ceramic method). Furthermore, in situ oxidation of the samples took place leading to oxidized products, such as La 2 Ba 2 Cu 2.15 Ti 2 O 11 , which earlier could have been obtained only by high oxygen pressure (5 kbar) annealing.

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